window.onload = function() {
    let regBtn = document.getElementById("a");
    regBtn.addEventListener('click', function() {
        open('./../HTML/test01.html')

    })
    window.onload = function() {
        let regBtn = document.getElementById("b");
        regBtn.addEventListener('click', function() {
            open('./../HTML/test.html')

        })
    }
}